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Title: Superconducting proximity effect in a topological insulator using Fe(Te, Se)

Journal Article · · Physical Review B
 [1];  [1];  [1];  [1];  [2];  [2];  [2];  [1];  [1]
  1. Boston College, Chestnut Hill, MA (United States). Dept. of Physics
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)

Interest in the superconducting proximity effect has recently been reignited by theoretical predictions that it could be used to achieve topological superconductivity. Low- Tc superconductors have predominantly been used in this effort, but small energy scales of ~1 meV have hindered the characterization of the emergent electronic phase, limiting it to extremely low temperatures. In this work, we use molecular beam epitaxy to grow topological insulator Bi 2Te3 in a range of thicknesses on top of a high- Tc superconductor Fe(Te,Se). Using scanning tunneling microscopy and spectroscopy, we detect Δind as high as ~3.5 meV, which is the largest reported gap induced by proximity to an s -wave superconductor to date. We find that Δind decays with Bi2Te3 thickness, but remains finite even after the topological surface states have been formed. Finally, by imaging the scattering and interference of surface state electrons, we provide a microscopic visualization of the fully gapped Bi2Te3 surface state due to Cooper pairing. Lastly, our results establish Fe-based high- Tc superconductors as a promising new platform for realizing high- Tc topological superconductivity.

Research Organization:
Energy Frontier Research Centers (EFRC) (United States). Center for Emergent Superconductivity (CES); Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); US Army Research Office (ARO); National Science Foundation (NSF)
Grant/Contract Number:
SC0012704; W911NF-17-1-0399; NSF-DMR-1654041; FG02-99ER45747
OSTI ID:
1462410
Alternate ID(s):
OSTI ID: 1441022
Report Number(s):
BNL-207884-2018-JAAM; PRBMDO; TRN: US1902167
Journal Information:
Physical Review B, Vol. 97, Issue 22; ISSN 2469-9950
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 18 works
Citation information provided by
Web of Science

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Cited By (2)

Effect of Sintering Temperature on the Superconductivity of Bi2Se3/FeSe0.5Te0.5Composites journal January 2020
Proximity-induced superconductivity in a topological crystalline insulator journal December 2019

Figures / Tables (4)